Conventionally, capacitors are known that have: a capacitor main body that is impregnated with an electrolytic solution; and a vessel that seals the capacitor main body. In capacitors of this kind, if gas is generated by the capacitor main body by charging and discharging the capacitor main body repeatedly, then there is a risk that internal pressure in the vessel gradually may rise, damaging the vessel.
Conventionally, in order to adjust the internal pressure of the vessel, capacitor pressure regulating apparatuses have been proposed that have: a gas venting valve that releases gas that is inside the vessel out of the vessel if the pressure inside the vessel exceeds a predetermined pressure, while preventing entry of external gas into the vessel; and a semipermeable film that is a porous membrane that covers the gas venting valve from inside the vessel, and that stops penetration of an electrolytic solution that is inside the vessel, while allowing the gas that is inside the vessel to permeate (see Patent Literature 1 and 2, for example).